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Das BELLE Experiment

Das BELLE Experiment. Mt. Tsukuba. KEKB. Belle. ~1 km in diameter. Gerhard LEDER Hephy ÖAW-Wien. KEK 　高エネルギ Tokyo 東京. Das Experiment. B-Physik. Überblick über neueste Resultate. BB threshold. L peak = 1.4 x10 34 cm -2 sec -1 design = 10 34 cm -2 sec. KEKB Collider. e -. e +.

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Das BELLE Experiment

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  1. Das BELLE Experiment Mt. Tsukuba KEKB Belle ~1 km in diameter Gerhard LEDER Hephy ÖAW-Wien KEK　高エネルギ Tokyo 東京 • DasExperiment • B-Physik • Überblick über neueste Resultate

  2. BB threshold Lpeak=1.4 x1034cm-2sec-1 design=1034cm-2sec KEKB Collider e- e+ 8GeV 3.5GeV = 0.425 bg B-Factory (on the 4s resonance) BB threshold

  3. Kontinuierliche Injection Kein Grund, Run zu unterbrechen Immer bei ~max. Strömen, Luminosität [CERN courier Jan/Feb 2004] both KEKB & PEP-II ~30% more L dt normal injection (old) continuous injection (new) HER current LER current Luminosity ~1 fb-1/day ! (~1x106 BB) - 0 12 24 Time

  4. SVD Der BELLE Detektor

  5. Unterschied SVD1.6 und SVD2.0 Rbeampipe 15 mm Rbeampipe 20 mm Rlayer 1 20 mm Rlayer 1 30 mm Routside 88 mm Routside 60 mm 8+10+14=32 Ladders 6+12+18+18=54 Ladders SVD1 SVD2

  6. Wiener R/O & Trigger Elektronik R-Z Trigger R-PHI Trigger 2 x 18 FADCTF 24 input OR and analog signal input from VATA

  7. * VudVub 2(a) * Vtd Vtb 3(g) 1(b) Vcd Vcb * B Zerfälle und das Standard Modell Quark level Electro-weak Hadrons QCD/Lattice New Resonances Final state b-quark: Heavy  variety of decay modes Reiches Feld für fundamentale SM Parameter

  8. b b W x t s,d s,d g,g,Z B Zerfälle und “Neue” Physik Experimental measurements agree? SM predictions Yes No Deeper understanding New Physics ? Key point:ANP ~ ASM(small/forbidden) Penguin + New particle, Phase

  9. Prozedur, um B Signal zu extrahieren Verwende spezielle Kinematik des Y(4S) Two almost independent variables MB and DE can be used to select B meson signal: * MB = (Ebeam)2 – (S Pi)2 DE = SEi - Ebeam * Methods to extract B signal yield: 1) Cut on MB and fit to DE 2) Cut on DE and fit to MB 3) Double dimensional fit to MB and DE distribution 4) If B->P1P2P3: cut DEand MB box and look at resonant structures in M(P1P2) mass distribution.

  10. qq e- e+ Other B continuum Y (4S) e+ e- - BB Signal B Continuums Unterdrückung Dominanter Untergrund für seltene Zerfälle: Continuum e+e-qq “continuum” (~3x BB) Jet-like To suppress: use event shape variables BB sphärisch

  11. Continuums Unterdrückung • To separate spherical BB events from jet-like continuum events, topological variables are used: • Second Fox-Wolfram moment • Super Fox-Wolfram • (six modified Fox-Wolfram moments, Fisher discriminant) • 3) Angle between B meson and • beam axis direction • 4) Angle between thrusts of • selected B meson particles and all other particles in event • Likelihood ratio includes all info.

  12. Die Standard Modell Physik bei BELLE dsb u Vud Vus Vub c Vcd Vcs Vcb t Vtd Vts Vtb B0->ππ B0->rπ B0->J/Ks B0->fKs B0->D(*) D(*) B0-> D*π B0->D*r B->DCPK CKM-Matrix {i=1,k=3}: Vub*Vud+Vcb*Vcd+Vtb*Vtd = 0 Vub*Vud Vcb*Vcd Vtb*Vtd Vcb*Vcd  + 1 + = 0 -(rih) -(1-rih) selbstkonsistent falls SM korrekt rih Unitaritäts Dreieck rih Vtb*Vtd Vcb*Vcd f2 Vub*Vud Vcb*Vcd (a) f3 f1 1 (g) (b) 0

  13. Direkte CP-Verletzung:B  Kp/pp W _ _ s/d Vtb t K/p+ W u s/d g K/p+ u u Vub 0 d B _ _ G(Bf ) - G(Bf ) p- p- d d u d d _ _ G(Bf ) + G(Bf ) ACP = 0 d B b b Vus/d Vts/d   Tree Penguin • Simplest charmless rare decay modes • Tree - Penguin interferenceDirect CP Violation Key prediction of Kobayashi-Maskawa model Understanding of Penguin Anomaly (New Physics)

  14. 275M BB Neu ACP(B0 K+p-) _ B0 K-p+ B0 K+p- Signal: 2139 53 [submitted to PRL] ACP = -0.101  0.025  0.005 3.9ssignificance [PID efficiency bias correction: dA = -0.01  0.004] Evidenz für DCPV bei Belle auch bei [A(p+p-) 3.2s]

  15. Time-Dependent CP Asymmetry • The CP violationmanifests itself inproper-time differencedistributionsof two B meson decays. • The time-dependent CP asymmetry ACPis: • Standard Model prediction:Sccs= sin2f1, Accs= 0Ssss= sin2f1, Asss= small

  16. Prinzip der Messung BCP e-: 8.0 GeV e+: 3.5 GeV e- e+ fCP (J/yK0) (4S) bg ~ 0.425 Btag DzcbgtB ~ 200 mm Flavor tag Dz • Rekonstruiere BJ/yK0 Zerfälle • Messe Eigenzeit Differenz: Dt • Bestimme flavor von Btag • Berechne CP Asymmetry aus beiden Dt Verteilungen

  17. Prinzip der f1-Messung mit B  J/y Ks Flavor-tag decay (B0 or B0 ?) J/ e fCP e t=0 KS z B - B B + B more B’s more B’s t z/(cβγ)

  18. sin2f1 mit 152106BB Paaren K. Abe et al. [Belle collaboration], BELLE-CONF-0436. 4347 signal events @ 152106BB poor flavor tag consistent with no direct CPV • Decay modes used: • J/yKS(p+p-), J/yKS(2p0), y(2S)KS, cc1KS, hcKS • J/yK*(KSp0) • J/yKL good flavor tag

  19. Lebensdauer und Mixing mit neuem Detektor Parameter fit results(with new detector only) Belle preliminary Belle preliminary [ps] Belle preliminary [ps] [ps-1] Previous data sets and fitting function for them are unchanged. New detector resolution is well understood. Belle preliminary

  20. Indirect CP Violation:Mixing und/oder • Tree - Penguin interference B0 J/y Vcb KS V*2 td B0 B0 V* J/y Vcb td Vtb KS V* Vtb td sin2f1(bgsqq) = 0.41  0.07 sin2f1(bgccs) = 0.726  0.037 CP violation “same” as J/Ks within the Standard Model (SM) Penguin~O(l2), Tree~O(l4) deviation = O(1)%

  21. 275M BB pB* B0f K0 [hep-ex/0409049] fKS Nsig=139 14 fKL purity 0.63 Nsig= 36 15 purity 0.17 Similar to J/yKL recon. + sophisticated continuum suppression includes Ks p0po (Nsig=13 5)

  22. 275M BB S = 0.736 fit B → fK0CPV Resultat [hep-ex/0409049] Poor tags Good tags fKS+fKL:S(fK0) = +0.06 ±0.33 ±0.09 A(fK0) = +0.08 ±0.22 ±0.09 “sin2f1”~2.2s away from SM

  23. BABAR Resultate für B0fK0 BABAR 227MBB pairs - BABAR-CONF 04/033

  24. S = 0.736 fit B0 → wKS & f0(980)KS New modes ! wKS f0(980)KS Nsig=31 7 purity 0.56 Nsig=102 18 purity 0.58 “sin2f1” Raw Asymmetry Good tags Good tags (~0s @SM) (~2.9s @SM) S = +0.75 0.64 -S = -0.47 0.41 0.08 A = +0.26 0.48 0.15 A = -0.39 0.27 0.08 0.13 0.16

  25. sin2f1 from bgs penguins at FPCP04 sin2f1(bgsqq) = 0.41  0.07 sin2f1(bgccs) = 0.726  0.037 CL = 0.00012 (3.8s)

  26. „Neue“ Physik bei B f K0 ? • B f Ks theoretisch verstanden • A = 0.08 ± 0.22 ± 0.09 • sin2f1eff= 0.06 ± 0.22 ±0.09 • 2,2 s Abweichung von „SM“ sin2f1(bgsqq) = 0.41  0.07 sin2f1(bgccs) = 0.726  0.037 CL = 0.00012 (3.8s) SM predicts same CPV in b ccs and sqq. New physics may deviate CPV in b ccs from sqq New process with different CP phase SM penguin f +

  27. ZukünftigeUntersuchungen: Radiative and EW Penguins b→sg, sl+l- decays proceed via FCNCBox and penguin diagrams b→sg • Br(b→sg) ≈ 3.5×10-4 • Br(b→sl+l-) ≈ aem×Br(b→sg) ≈ 10-6 • New particle (via loops) may make appreciable contribution to decay rates and/or asymmetries. • Good testing ground of SM and beyond SM. b→sl+l-

  28. X(3872) Produktion in B Zerfällen Recently, Belle observed the X(3872) in B+->X(3872) K+ decay, with X(3872)->J/Y p+p- (confirmed by CDF, D0 and BaBar). Br(B-K-X3872) Br(X3872p+p-J/y) = 0.063 ± 0.012 ± 0.007 Br(B-K-y’) Br(y’p+p-J/y) 35±7 events M=3872.0±0.8 MeV G<2.3MeV (90%) Y ’ M(J/Yp+p-) X(3872) M(J/Y p+p-) – M(J/Y)

  29. Charmonium Spektroskopie cc1’ hc2Y2 Y3 hc’ cc2 cc1 cc0 Decay to J/Yp+p- Isospin 0++ allowed J/Y Isospin 1-- violating hc < 1 MeV/c2 hc’’ X(3872) MD*+MD 2MD Y’ hc

  30. Studie der X(3872) Produktion in B Zerfällen • Search for B gX(3872)K decay, with X(3872)gcc2g. MB DE 152x106 BB pairs G (Xgcc2g) = 0.42 ± 0.45 ± 0.23 <1.1 (90%CL) G(XgJ/Yp+p-) • Search for B gX(3872)K decay, with X(3872)gJ/Y g. MB MX DE G (XgJ/Y g) = G(XgJ/Yp+p-) 0.22 ± 0.12 ± 0.06 <0.40 (90%CL) |cos q| nHelicity angle: if Jp=1+- (hc’), sin2q angular distribution is expected. g ruled out by data. X

  31. events with M(3p)>0.75 GeV These events are almost pure signal Nevt=10.0 ± 3.6 S/N = 5/1 Signif = 5.8s Studie vom B+ X(3872) K+ Zerfall, X(3872)J/Y p+p-p0 274x106 BB pairs Events within B signal region and mass interval: | M(J/Y p+p-p0) – 3872. | < 12 MeV/c2 Assuming events with M(3p) > 0.75 as J/Yw : G (XgJ/Yw) = 0.8 ± 0.3 (stat) ± 0.1(syst) G(XgJ/Yp+p-) It provides support for DD* molecular interpretation of X(3872).

  32. M too low and G too small angular dist’n rules out 1+- G(gJ/y) way too small G(gcc1) too small; (PRL 93, 2003) pp hc should dominate ppJ/y G( gcc2 & DD) too small Welcher Zustand ist X(3872)? _ Keine guten cc Kandidaten für X(3872): hc” hc’ cc1’ y2 hc2 y3 - Isospin violating decays to J/Yp+p-

  33. q q Neue Charmonium Resonanz ? • Interpretation: • Masse gerade an der D0D*0 Schwelle • lose gebundenes “molecular charmonium”, oder ein Y(13D2) Zustand? • Ersteres in der Literatur diskutiert seit 1975: • ausgelöst durch komplizierte Struktur vons(e+e- ->hadrons) bei SPEAR • M. Bander, G.L. Shaw, P. Thomas, PRL 36, 695 (1976) • M.B. Voloshin, L.B. Okun JETP Lett. 23, (1976), Pisma Zh.Eksp.Teor.Fiz.23, 369 (1976) • A.De Rujula, H.Georgi, S.L.Glashow, PRL 38 (1977) • WW beschrieben durch p-Austausch gibt attraktive Kraft für DD*, BB* • N.A. Tornqvist, PRL 67, 556 (1991), Z.Phys. C61, 525(1994) • A.V. Manohar, M.B. Wise,Nucl.Phys. B339, 17(1993) D0D*0 Molekül q Ältere Ideen: q Q Q Q Q Stärkere Bindung Lose Bindung Decays to (QQ)+(light mesons) via quark rearrangement which suppresses the width. Diquark Model (Qq) are colored sin2f1 (NEW World Av.) =0.736±0.049

  34. Zusammenfassung (1) SM bisher überraschend selbst in Details erfüllt! Bestimmung der CKM-Matrix-Elemente im SM Indirekte CP-Verletzung A(t) bestimmt mit hoher Präzision sin2f1(bgccs) = 0.726  0.037 Grosse Anstrengung auch die beiden anderen Winkel zu messen (f2 und f3) Außerdem „Seitenlängen“ des Dreiecks: Dmd und Dms, sowie Vub/Vcb etc. sin2f1(bgsqq) = 0.41  0.07 Bedeutet anderer Wert (3.8 s) schon „neue Physik“ oder „nur“ Penguin-Beitrag ?

  35. Zusammenfassung (2) Beträchtliche Direkte CP-Verletzung (3.9 s ) ACP (B0 K+p -) = -0.101  0.025  0.005 Asymmetrie Materie-Antimaterie im Universum ? Molekül D*0D0 = 4 Quarkzustand oder konventionelle Erklärung? Neues Gebiet: Ds- Spektroskopie etc. BELLE ist bei vielen Gebieten an vorderster Front: SUPERBELLE mit höherer Luminosität

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